I've never read anything so unreasonable. Before you jump the gun, maybe you should read the following and actually think about what you're saying.
Firstly, this is a very brief explanation of how Down's screening works:
It's a combined test. Emphasis on COMBINED. Your bloods are combined with the fluid level in the back of the neck, along with a whole host of information such as your smoking status, ethnic origin etc etc.
This gives you a risk. A probability of your child having a chromosomal condition. The fluid in the back of the neck CANNOT give this information alone, and even if you don't consent to Down's screening, that fluid, if raised, can be raised for OTHER reasons that aren't necessarily genetic.
Your child could have a fatal heart condition, or may never be able to fully develop a lymphatic system. You would be told, consenting to Down's or not, as the fluid measurement could be higher for reasons not directly linked to Down's. So, whether you want screening or not, the sonographer would have to say if it was abnormally high, in the same way they'd have to tell you if there was a part of the brain missing. You are still technically being screened for health when you have these scans, just not down's if you don't consent to that element of it. It isn't a baby bonding service. It's a serious medical exam.
So, in being told the fluid is normal, it's the same as being told the brain looks good so far, the arms and legs seem fine etc etc. You haven't been told you that you don't have a child with Down's syndrome. At. All. You may very well. You've elected not to know, and that's your choice. It WAS respected.
This sonographer may not have worded things in the way you wanted, but let's be clear, no harm has been done and you have not been screened for a chromosomal abnormality against your will. You do have a choice and it has NOT been violated. THAT'S the important take home message here, if you'll be even the slightest bit reasonable.
Just so you know, for your twenty week scan, there are 11 life threatening conditions that are assessed. Even if one is found, whether it is present as an isolated structural abnormality or due to a Trisomy that you don't want to know about, no one makes you do anything. You always have a choice. These systems are here in place to support families and provide them with all the care they need for whichever path they chose to go down. It's an amazing service that is often taken for granted.
The sonographer would have looked at the brain, beating heart, limbs, they're always assessing the back of the neck, as if it is above a certain mark they HAVE to tell you, and no, that is not telling you that your child definitely has Down's syndrome. It's flagging a concern, of which you would be counselled and THEN if you WANTED you may be screened, on top of a whole host of other things. The fluid could be raised FOR OTHER REASONS.
But no, assume the Sonographer violated your choice by telling you your baby looks healthy.
That's obviously the reasonable thing to do.
A someone who has worked in heath care and has a young relative who had a problem flagged, I truly feel like I can appreciate this matter. It is very important to me. Be glad your child is healthy. And no, you don't know if your baby definitely doesn't have Down's syndrome just because the sonographer said the neck looks okay.
Unbelievable.